English Grammer - some definition

Subject : It denotes the person or thing about which something
is said. It can be a noun, a pronoun, an infinitive, a
gerund, a noun phrase or clause.

Verb : Write, read... are called transitive verbs. Trasitive
verbs have objects. Sleep, come, go, become.... are
called intransitive verbs. They have no objects. If
the transitive verbs have two objects (answer to what
and to whom) they are called ditransitive verbs.

Object : The object that answers the question ‘what’ is the
DO. The object that answers the question ‘to whom’
is IO.

Complement : It completes the predicate of a sentence. It is an
essential part. The subject complement describes or characterises the subject. The object complement
describes or characterises the object.
Adjunct : It gives additional meaning. It answers to the
question how (manner), when (time), where (place)
etc.